Bump slotmap from 1.0.5 to 1.0.6 (#3809)

Bumps [slotmap](https://github.com/orlp/slotmap) from 1.0.5 to 1.0.6.
- [Release notes](https://github.com/orlp/slotmap/releases)
- [Changelog](https://github.com/orlp/slotmap/blob/master/RELEASES.md)
- [Commits](https://github.com/orlp/slotmap/compare/v1.0.5...v1.0.6)

---
updated-dependencies:
- dependency-name: slotmap
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>